1. Field of the Invention
The present invention relates to highly luminescent display cells.
2. Description of the Prior Art
A large-sized display apparatus has been proposed which consists of a multiplicity of luminescent display cells, each cell having luminescent trios composed of three phosphor layers which emit red, green and blue light, so as to produce a large-picture screen, for example, 40 meters wide by 25 meters high.
As illustrated in FIGS. 28 and 29, such a luminescent display cell is constructed so that the three phosphor layers 2 (2R, 2G, 2B) for emission of red, green and blue light are formed by coating the inner surface of a front panel 1A of a glass housing 1. The phosphor layers are surrounded with a dark layer 3, for example, carbon. Furthermore, the three wire cathodes K (K.sub.R, K.sub.G, K.sub.B), three first grids (control electrodes) G.sub.1 (G.sub.1R, G.sub.1G, G.sub.1B) and a common second grid (accelerating electrode) G2 are disposed opposite to the three-color phosphor layers 2R, 2G and 2B, respectively.
The phosphor layers 2R, 2G and 2B are surrounded with a separator 4, and electron beams from the wire cathodes K radiates toward or directed to the corresponding phosphor layers 2 individually. An anode terminal 5 for applying an anode voltage to the phosphor layers 2 extends out from the glass housing 1 via the separator 4 from between the front panel 1A and the sidewall plate 1C. The terminals 6 for the cathodes K, first grids G1 and second grid G2 extend from the housing between the rear panel 1B and the sidewall plate 1C. In this luminescent display cell, an anode voltage is applied to the phosphor layer 2 through the anode terminal 5, and the voltage between the anode and the second grid G2 is fixed and the phosphor layers selectively activated with regard to the on-off state in accordance with the voltage applied to the first grid G1.
The display apparatus employing such luminescent display cells is advantageous in the capability of producing a huge picture, but there exists a disadvantage as well in that the display of a moderate-size picture is not easily achievable. Therefore, it is desirable to attain adequate dimensional reductions.
These and other objects of this invention will become apparent from the following description and appended claims.